Yosemite crews to continue working Washburn Fire through night; Mariposa Grove a priority

With the Washburn Fire now consuming more than 2,000 acres at the southern end of Yosemite National Park and hot and dry weather expected through the week, fire crews will work through Sunday night, attacking the blaze.

“We’ll have a full night crew out, building containment lines and protecting Mariposa Grove as best they can,” an incident management team spokesperson said.

There were 545 fire personnel on Sunday working the wildfire, which started on Thursday near the Washburn Trail in the Mariposa Grove area of the park and is burning through areas of heavy dead and downed trees.

The cause of the fire, which has consumed 2,044 acres and is 0% contained, is under investigation. Through Sunday afternoon, no structures have been damaged or destroyed. But with the weather warming, fire activity will increase on Monday and is expected to remain actively spreading through the week.

The Washburn Fire had grown by almost 50% to 1,591 acres overnight Saturday and Sunday morning. Through Sunday afternoon, another 453 acres had burned.

Within the Mariposa Grove, rangers have set up portable sprinkler systems to protect one of the park’s most well-known giant sequoias, the Grizzly Giant. In addition to moistening the forest floor around the tree, said Nancy Phillipe, a fire information spokeswoman for Yosemite National Park. The sprinklers also raise the humidity in the grove to reduce the dry conditions that could fuel flames.

The Mariposa Grove is the largest stand of massive giant sequoias in Yosemite, with more than 500 mature specimens of the iconic trees. The grove was the first area of what is now Yosemite National Park when President Abraham Lincoln signed legislation in 1864 to protect Mariposa Grove.

Rangers opted against wrapping the base of the Grizzly Giant – a 209-foot-tall, 3,000-year-old sequoia described as the second largest in the grove – and other giant sequoias within Mariposa Grove with a foil-like retardant material for fear of creating more of a “baked potato” effect if flames did sweep through the area, Phillipe said. But, she added, the wrapping was used to envelop a historic cabin in the grove.

Firefighters said that previous prevention efforts within the grove, including prescribed burns and other measures to reduce fuels, could prove beneficial in minimizing the Washburn fire’s threat.